Two experiments investigated whether priming due to a match in just the onset between a masked prime and target is found with high-frequency target words. Forster and Davis (1991, Exp. 5) reported that the masked onset priming effect was absent for high-frequency words and used the finding to argue that the effect has its locus in the grapheme-phoneme mapping process that operates serially within the nonlexical route. Experiment 1 used primes that were unrelated to targets and found a masked onset priming effect of equal size for high-frequency and low-frequency target words. Experiment 2 used form-related primes as used by Forster and Davis, and again found that the effect of onset mismatch was not dependent on target word frequency. These results are interpreted in terms of an alternative view that the masked onset priming effect has its origin in the process of preparing a speech response.